diff --git a/importlib_resources/tests/test_open.py b/importlib_resources/tests/test_open.py
index bb75d87..44f1018 100644
--- a/importlib_resources/tests/test_open.py
+++ b/importlib_resources/tests/test_open.py
@@ -24,7 +24,7 @@ def test_open_binary(self):
         target = resources.files(self.data) / 'binary.file'
         with target.open('rb') as fp:
             result = fp.read()
-            self.assertEqual(result, b'\x00\x01\x02\x03')
+            self.assertEqual(result, bytes(range(4)))
 
     def test_open_text_default_encoding(self):
         target = resources.files(self.data) / 'utf-8.file'
diff --git a/importlib_resources/tests/test_read.py b/importlib_resources/tests/test_read.py
index 6c512ce..97d9012 100644
--- a/importlib_resources/tests/test_read.py
+++ b/importlib_resources/tests/test_read.py
@@ -19,7 +19,7 @@ def execute(self, package, path):
 class ReadTests:
     def test_read_bytes(self):
         result = resources.files(self.data).joinpath('binary.file').read_bytes()
-        self.assertEqual(result, b'\0\1\2\3')
+        self.assertEqual(result, bytes(range(4)))
 
     def test_read_text_default_encoding(self):
         result = (
@@ -60,13 +60,13 @@ class ReadZipTests(ReadTests, util.ZipSetup, unittest.TestCase):
     def test_read_submodule_resource(self):
         submodule = import_module('data01.subdirectory')
         result = resources.files(submodule).joinpath('binary.file').read_bytes()
-        self.assertEqual(result, b'\4\5\6\x07')
+        self.assertEqual(result, bytes(range(4, 8)))
 
     def test_read_submodule_resource_by_name(self):
         result = (
             resources.files('data01.subdirectory').joinpath('binary.file').read_bytes()
         )
-        self.assertEqual(result, b'\4\5\6\x07')
+        self.assertEqual(result, bytes(range(4, 8)))
 
 
 class ReadNamespaceTests(ReadTests, unittest.TestCase):
@@ -82,7 +82,7 @@ class ReadNamespaceZipTests(ReadTests, util.ZipSetup, unittest.TestCase):
     def test_read_submodule_resource(self):
         submodule = import_module('namespacedata01.subdirectory')
         result = resources.files(submodule).joinpath('binary.file').read_bytes()
-        self.assertEqual(result, b'\x0c\x0d\x0e\x0f')
+        self.assertEqual(result, bytes(range(12, 16)))
 
     def test_read_submodule_resource_by_name(self):
         result = (
@@ -90,7 +90,7 @@ def test_read_submodule_resource_by_name(self):
             .joinpath('binary.file')
             .read_bytes()
         )
-        self.assertEqual(result, b'\x0c\x0d\x0e\x0f')
+        self.assertEqual(result, bytes(range(12, 16)))
 
 
 if __name__ == '__main__':